1. Field of the Invention
The present invention relates to a vacuum processing apparatus, and more particularly, to a vacuum processing apparatus such as a sputtering apparatus or a dry-etching apparatus which is suitable for effecting a predetermined treatment with respect to a sample under decreased pressure.
2. Description of the Prior Art
Among vacuum processing apparatus such as sputtering apparatus and dry-etching apparatus for performing such predetermined treatments as film forming treatment and etching treatment, a well-known vacuum processing apparatus disclosed, for example, in the specification of Japanese Patent Laid-Open No. 93363/1979, adopts a method wherein the sample is carried between the outside portion and a main vacuum chamber where the sample is subjected to a predetermined treatment in such a way that the sample surface to be treated is so directed in an upward direction as to assume a horizontal attitude.
The sample is conveyed in such a manner that the sample surface to be treated is so directed in an upward direction as to maintain its horizontal attitude, this, however, creates a problem. Namely, foreign substances such as dust or the like which are present in the atmosphere through which the sample is carried become adhered to the sample surface to be treated during its conveyance. The thus adhered foreign substances deteriorate the quality of treatment, thereby causing a decrease in the manufacturing yield of a semiconductor element. Semiconductor elements are rapidly advancing nowadays in regard to their accuracy. The adhesion of foreign substances on the sample surface to be treated is considered to be one of the most acute problems presently faced.
Recently, for instance, an apparatus has been disclosed in the specification of Japanese Patent Laid-Open No. 197145/1984. In this disclosure, a method is proposed wherein the sample is carried with a surface to be treated being retained upright, i.e., in a vertical position, this contriving to constrain the adhesion of foreign substances on the sample surface to be treated at the time of the sample being conveyed. To be specific, the arrangement is such that the sample is carried between a treatment chamber and a portion in the atmosphere outside of the treatment chamber through a load lock station which is formed by a part of the treatment chamber employed as the main vacuum chamber in such a manner that the sample surface to be treated is held vertical. In this apparatus, the sample is conveyed while being held vertical, and hence the adhesion of foreign substances on the sample surface to be treated is constrained. On account of its constitution wherein the sample is carried between the treatment chamber and a portion of the atmosphere outside of the treatment chamber only through the load lock station, the vacuum load is, however, increased. This causes problems as regards properly maintaining the pressure within the treatment chamber, the factor exerting a great influence on the quality of treatment with respect to the sample.